Offset is a direct current (DC) parameters of an operational amplifier. The offset of an operational amplifier is not constant but changes if the operating temperature of the amplifier changes. The change of offset is referred to as offset drift. In order to reduce offset and offset drift, many amplifiers are trimmed at the wafer or package level. Bipolar input amplifiers (i.e., amplifiers implemented as an integrated circuit that use bipolar transistors coupled to the amplifier input) generally have a single trimming step at one temperature because the offset and offset drift are correlated. If the offset is trimmed to be zero, the offset drift will usually also be zero. Amplifiers having junction field effect transistor (JFET) or complementary metal oxide field effect transistor (MOSFET) input stages generally have more than one trimming step as offset and offset drift are not correlated. In order to reduce offset and offset drift in JFET or MOSFET amplifiers, a two-step trimming method can be applied. The amplifier is then adjusted in two consecutive steps at two different temperatures.
An example of a conventional circuits and/or methods are: U.S. Patent Pre-Grant Publ. No. 2003/0155974; and German Patent No. DE10132803.